jar file execution

[Gopu Akraju]

I have developed a swing application and executing under linux environment. jar file is present under /deo/temp/testing.jar. I have two issues to share now.

1. If I execute my jar file under /deo/temp> java -jar testing.jar, I am able to see my application start running. But if I try like /deo>java -jar /temp/testing.jar, I get the error message "Main method not found"
How do I resolve this problem?

2. How do I create an icon so that when the user clicks the jar file, it starts executing. In windows, as I have developed using netbeans, if I double click the ajr file found under dist folder, the program starts executing. As the users are not aware of using command line prompt, I am supposed to make an icon on double clicking should start the program.

It would be very useful if I hear some expert advice on both the issues I have mentioned above. Thanks.

[Mark Freeman]

Hey there.

1. The leading / tells the system to start with root. If you want to start from the current directory, add a ".".

/deo>java -jar [B]./temp/testing.jar    [/B]

2. You could create a .bat file with the cmd line commands in there. I think most systems will automatically run a jar file if the jre is install and added to the system's PATH setting.

[Rob Spoor]

Originally posted by Gopu Akraju:
I have developed a swing application and executing under linux environment. jar file is present under /deo/temp/testing.jar. I have two issues to share now.

1. If I execute my jar file under /deo/temp> java -jar testing.jar, I am able to see my application start running. But if I try like /deo>java -jar /temp/testing.jar, I get the error message "Main method not found"
How do I resolve this problem?

Should that second not be

/deo>java -jar temp/testing.jar

?
Without the / before temp? Because now you are trying to access file /temp/testing.jar, not /deo/temp/testing.jar

2. How do I create an icon so that when the user clicks the jar file, it starts executing. In windows, as I have developed using netbeans, if I double click the ajr file found under dist folder, the program starts executing. As the users are not aware of using command line prompt, I am supposed to make an icon on double clicking should start the program.

It would depend on the Window and Desktop manager you're using. In Windows it works because when you install the JRE, it automatically creates a file association for JAR files to be opened with javaw.exe.

In GNOME or KDE you'll probably have to create such a file association yourself; please check the GNOME / KDE documentation on how to. Alternatively, you can create a shortcut for the users that executes "javaw <your JAR file>"

[Gopu Akraju]

Itried running as suggested

java -jar ./temp/testing.jar
Exception in thread "main" java.lang.NullPointerException
        at testing.testing.createGUI(testing.java:217)
        at testing.testing.<init>(testing.java:97)
        at testing.testing.main(testing.java:90)

[Campbell Ritchie]

now you need to go through the usual procedure for debugging a NullPointerException. Please search the forum for NullPointerException; it comes up frequently

[Gopu Akraju]

Can this be solved by setting the path for my instance of jar file? No idea about linux environment. Thanks.
[ May 08, 2008: Message edited by: Gopu Akraju ]

[fred rosenberger]

moving thread at users request.

[luisrd]

For those who have trouble with Vista and double clicking on Jar files.
Where JAR files say Main not found. The resolution is to clear the file association with "ASSOC .JAR=" and then set it back to "ASSOC .JAR=jarfile"

Close your windows and go back to the folder. You should be able to double click now.

[Bear Bibeault]

"LuisJava", please check your private messages for an important administrative matter.

[Paul Clapham]

gauravtyagi tyagi,
Your post was moved to a new topic.